The African Union says Sudan must stop the aerial bombardment of South Sudan and has called on both countries to cease hostilities immediately.

A statement from the AU Peace and Security Council says the two countries must withdraw their forces from the disputed border region and keep their troops within their borders.

The statement released after a council meeting late Tuesday, said that the two neighbours should also stop issuing inflammatory statements and propaganda that could escalate the conflict. South Sudan's president said Tuesday that Sudan has declared war on his country following the north's repeated bombing of the south.

Sudan and South Sudan have been drawing closer to a full-scale war in recent weeks over the unresolved issues of oil revenues and their disputed border.